What is the role of somatosensory evoked potentials (SEPs) in the workup of lumbosacral disk disease?

Updated: Oct 25, 2019
  • Author: Andrew B Evans, MD; Chief Editor: Selim R Benbadis, MD  more...
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Sitzoglou et al identified clear dermatomal SEP abnormalities that correlated with radiculopathy in as many as 83% of the cases studied. [50] Electromyography (EMG) yielded positive results in about 63% of the same subjects. Thus, dermatomal SEPs may complement routine electrophysiologic testing of patients with radiculopathy and may provide a sensitive noninvasive technique for defining the level of disk prolapse.

This study included 24 patients with unilateral radiculopathy, all of whom had clinical signs and symptoms of disk prolapse and positive findings on neuroradiologic testing. [50] The latency and the amplitude of the first positive SEP waveform were measured, and both peripheral nerve conduction studies and EMG were performed.

Tsonidis et al reported on the diagnostic value of dermatomal SEPs by correlating the neurophysiologic data with clinical, neuroradiologic, and operative findings in 12 patients with surgically treated lumbar disk protrusion. [51] The retrospective study disclosed correlation of the SEPs after dermatomal stimulation and surgical findings in 83% of cases.

In this study, the diagnostic workup included a history, a neurologic examination, routine lumbar spine films, and computed tomography (CT) and magnetic resonance imaging (MRI) of the lumbar spine, in addition to neurophysiologic investigations, especially conduction velocity studies, and standard SEPs and dermatomal SEPs. [51]

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